SCIENCE OF THE DAY.

New Zealand Herald, Volume LXIV, Issue 19780, 29 October 1927, Page 5 (Supplement)

SCIENCE OF THE DAY.

THE IMPORTANCE OF INK,

A little reflection will show that the dissemination of knowledge, the pursuit qf pleasure, commercial development, and indeed the interchange of human activities in all their multitudinous phases depend, to a large exteat, says a recent writer, on one simple substance—ink. For both the present degree of intercourse and the record of past occurrences, which may be summed up in one word experience, would be impossible without those conventional marks on paper, wheh printing and printink render possible. Ink is, of course, a substance, which is made in various forms, depending on whether it is to bo used for writing, marking, typewriting, or printing. Each form can also be made in various colours, so as to provide the necessary degree of emphasis, distinction, or artistry. Of these, probably the most important are the inks used in printing, because, to be of any real value, they must possess the qualities both of clarity and permanence. Such inks are produced in great variety, and in the past were made chiefly from lamp black and linseed oil. The former substance has now become too expensive, and it has been displaced by resin black, soot, shale black, and other mineral matters, aniline colours or iron or manganese compounds, while linseed and castor oils have also largely bsen displaced by tar oils and mineral oils. For good and medium quality ink, however, polymerised or boiled linseed oil is still used, together with resin oil, soap, or resin soap and various pigments. Bitumen, ashphalt, or stearin pitch are also employed in admixture in some inks, particuarly those used for rotary press work, as they improve the covering properties and prevent the ink piercing the paper. BED WHICH PROMOTES SLEEP. Very wide interest is being taken in a bed designed to promote sleep, exhibited by Sir Alfred Yarrow at the annual conversazione of the British Institution of Civil Engineers on June 15 last. The design of the bed is based on the fact that Sir Alfred found that the movements of a train were conducive to sleep and those movements are simulated by the mechanism of the bed. Essentially the bed is of the usual wooden-frame type but is sup-

I ported on springs and given the required movement through a link mechanism ""driven by an electric motor. Sir Alfred found that a constant movement was likely to produce nausea and the amplitude of the motion of the bed has accordingly been arranged to vary gradually throughout a cycle. This is effected by having two eccentrics, which are driven from the motor through two gear wheels, one having a tooth less than the other so as to give a gradual angular advance of one eccentric with respect to the second throughout a complete cycle of 360 deg. A crossbar connecting the ends of the two eccentric rods is coupled at its centre to a rocking lever, and this, in turn, imparts a reciprocating motion to the frame of the bed. CONTROL OP MALARIA. Sir Ronald Ross, the director-in-chief of the Ross Institute and Hospital for Tropical Diseases, made last October a 20,000-mile journey to India and Malaya to inspect the progress of anti-malarial operations in those countries and his report on malaria control has been issued. Referring to the work of control carried out in Singapore he says:-r-"I was much impressed with the vigour and the extent of the malaria control exercised there and Dr. Hunter, the medical officer of health, told nie he was employing 400 men on the work within the town area and the cost was small compared with that which malaria would have inflicted on the city. No other city in the British Emp.re has, I believo, progressed so far in malaria control as Singapore. Each step taken has been preceded by a careful entomological as well as engineering surveys, and the problems have often presented considerable difficulties. The improvement is rapid and will -be better still in future. Malaria control in Malaya has reached a high state of efficiency, and, unless it is neglected in the future for any causes, will quite possibly succeed in practically banishing the disease, or at least in reducing the pandemic to small local outbreaks."